Technical Field
This disclosure relates to a fuel cell plate flow field configuration.
Description of the Related Art
A fuel cell includes an anode and a cathode arranged on either side of a membrane electrode assembly. The anode and the cathode are provided by a plate, which includes a flow field. The anode plate flow field delivers fuel to the membrane electrode assembly, and the cathode plate flow field delivers a reactant to the membrane electrode assembly.
The flow fields are provided by multiple channels that are provided fluid from an inlet manifold. The channels have been arranged in a variety of configurations depending upon a variety of factors, such as packaging constraints. Typically, it is desirable to provide a manifold that is wider than inlets to the channels to ensure a generally even distribution of flow across the channels. Occasionally, it is not possible to supply each of the channel inlets with unobstructed flow from the inlet manifold. As a result, some of the channels receive a somewhat limited flow, which results in an uneven distribution of flow across the flow field. Uneven flow distribution can create temperature gradients across the plate and reduce the efficiency of the chemical reactions within the fuel cell. In the case of anode flow fields, insufficient hydrogen at a location can create carbon corrosion of the anode plates. In the case of cathode flow fields, insufficient oxygen at a location can cause high temperatures and cell voltage dropoff.
What is needed is a fuel cell plate having a flow field with a generally even flow distribution in configurations where it is not possible to supply an uninhibited flow to at least some of the channels.